The present invention relates to a metal laminate gasket with an irregular size seal ring, in particular a seal ring with narrow and wide portions to securely seal around a hole in an internal combustion engine.
A metal gasket or metal laminate gasket is installed between two engine parts to securely seal around a sealing hole or hole to be sealed. Since high pressure and temperature are formed in or applied to the sealing hole in the engine, there have been proposed many sealing mechanisms.
In the sealing mechanism, generally, a high surface pressure is formed around the sealing hole to securely seal therearound. Especially, since high temperature and pressure are formed in a cylinder bore, bolts are arranged around the cylinder bore to apply high surface pressure around the cylinder bore.
In this case, if high pressure is applied immediately outside the cylinder bore, the cylinder bore may deform due to the high pressure applied from the bolts. Therefore, in the engine, the high pressure should not be simply applied around the cylinder bore.
In one type of the convention gaskets, a first metal plate is turned around a hole to be sealed to form a flange laminating on a base portion of the first metal plate, and a second metal plate is disposed on the base portion without overlapping the flange. In order to increase a surface pressure around the hole, a metal ring may be located between the flange and the base portion.
In this gasket, when the gasket is tightened, portions on the metal ring near the bolts receive high tightening pressures from the bolts, so that large sealing pressures are applied near the bolt holes around the sealing hole. As a result, the tightening pressures in other portions are inevitably reduced. When the tightening pressures around the sealing hole are considered as a whole, the surface pressures are not properly distributed to possibly cause leakage from the sealing hole.
The present invention has been made to obviate the above drawbacks, and an object of the invention is to provide a metal laminate gasket which can securely seal around a hole to be sealed.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein influences by local tightening pressures by bolts are minimized.
A further object of the invention is to provide a metal laminate gasket as stated above, wherein the surface pressure distribution can be easily controlled.
Further objects and advantages of the invention will be apparent from the following description of the invention.